| rosette test | A test for rosette-forming cells (T-lymphocytes) in which these cells and sheep erythrocytes, are incubated and centrifuged lightly, then examined under a microscope for rosette formation or adherence of erythrocytes to T lymphocytes. (05 Mar 2000) |
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| E-rosette test | A test to identify T lymphocytes by mixing purified blood lymphocytes with serum and sheep erythrocytes; rosettes of erythrocytes form around human T lymphocytes on incubation. (05 Mar 2000) |
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| rosette | <dermatology> A group of organs or other body features, such as leaves or hair, which are clustered and crowned around a common point of attachment. (09 Oct 1997) |
| rosette formation | The in vitro formation of clusters consisting of a cell (usually a lymphocyte) surrounded by antigenic cells or antigen-bearing particles (usually erythrocytes, which may or may not be coated with antibody or antibody and complement). The rosette-forming cell may be an antibody-forming cell, a memory cell, a T-cell, a cell bearing surface cytophilic antibodies, or a monocyte possessing fc receptors. Rosette formation can be used to identify specific populations of these cells. (12 Dec 1998) |
| rosette-forming cells | T lymphocytes with an affinity for sheep erythrocytes and which, when suspended in serum, bind the uncoated, nonsensitised erythrocytes in a rosette formation. (05 Mar 2000) |
| chromosome rosette | Right before metaphase, human chromosomes briefly form this single ring structure. (09 Oct 1997) |
| chromosome rosette john jordan | Right before metaphase, human chromosomes briefly form this single ring structure. (09 Oct 1997) |
| EAC rosette | <haematology> Rosettes formed from erythrocytes (E) coated with antibody (A) and complement (C). A test for C3b or C3bi receptors (CR1 or CR3). The rosettes form more easily then E or EA rosettes. See: E rosettes. (16 Mar 2000) |
| EAC rosette assay | <haematology> Rosettes formed from erythrocytes (E) coated with antibody (A) and complement (C). A test for C3b or C3bi receptors (CR1 or CR3). The rosettes form more easily then E or EA rosettes. See: E rosettes. (16 Mar 2000) |
| EA rosette | A test for the presence of Fc receptors. (18 Nov 1997) |
| E rosette | The adherence of erythrocytes to cells. Sheep erythrocytes will adhere spontaneously to human T-cells, forming rosettes. (05 Mar 2000) |
| Abbe test plate | <equipment> A long, wedge-shaped coverslip about 0.20 mm thick at one end and 0.10 to 0.12 mm at the other end coated chemically with a silver film on which are ruled horizontal lines. at each variation in thickness of 0.01 mm there are vertical lines. By means of oblique illumination and by focusing on different portions of the plate, it is possible to determine the optimum coverslip thickness for any objective and also, for microscopes with drawtubes, the tube length for best objective performance. The approximate freedom from spherical and chromatic aberrations can also be estimated. Small isolated bits of silver near the edges of the lines form good objects for the star test (05 Aug 1998) |
| acetone test | A test for ketonuria; the suspected urine is shaken up with a few drops of sodium nitroprusside, and strong ammonia water is then gently poured over the mixture; if acetone is present, a magenta ring forms at the line of contact; tablets containing sodium nitroprusside and alkali are now more commonly used. (05 Mar 2000) |
| achievement test | A standardised test used to measure acquired learning, e.g., competence in a specific subject area such as reading or arithmetic, in contrast to an intelligence test which is a useful index of potential ability or learning. (05 Mar 2000) |
| acidified serum test | Lysis of the patient's red cells in acidified fresh serum, specific for paroxysmal nocturnal haemoglobinuria. Synonym: Ham's test. (05 Mar 2000) |
| acid loading test | <nephrology> This is a test used in the diagnosis of renal tubular acidosis. The patient takes ammonium chloride capsules for 3 days to acidify the blood (lower blood pH). A sample of the urine and the blood is then collected and the results are interpreted. (27 Sep 1997) |